When this is done, it will probably the worlds smallest WiFi capable open-source EEG. At 62x36 mm it's smaller than your credit card while still having 8 channels, 24-Bit recording depth, and microvolt resolution. It uses a state of the art ADS1299 frontend to amplify and digitize the analog signals and an ESP32-S3 microprocessor to process the data and send it to a computer via WiFi. I've been working on this for over a year and it's nearing completion.
The image below shows the PCB layout. The whole image is the size of a normal credit card, giving you a sense of just how small it is!
